Domestic clothes drying appliance



J. w. JA coss 3,242,584

DOMESTIC CLOTHES DRYING APPLIANCE March 29, 1966 Filed April 29, 1963 2 Sheets-Sheet 1 Q) I48 E 2/2-- 200-- r2 Emropy INVENTOR. Fig. 2 James 4 Jacobs March 29, 1966 J, w, JACOBS 3,242,584

DOMESTIC CLOTHES DRYING APPLIANCE Filed April 29, 1963 2 Sheets-Sheet 2 ,Is 20 24 no Lso e6 INVENTOR.

32 James W Jacobs Fig. 4

H/s Aflorney United States Patent 3,242,584 DOMESTIC CLOTHES DRYING APPLIANCE James W. Jacobs, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Apr. 29, 1963, Ser. No. 276,409 7 Claims. (Cl. 3437) This invention relates to a domestic appliance and more particularly to a domestic clothes dryer.

In many conventional clothes dryer arrangements heated air is circulated through wet fabric tumbled by a rotatable drum or fabric enclosure for removing moisture therefrom. In such arrangements the time necessary to dry fabric is generally dependent upon the amount of heat supplied to the air being circulated through the tumbling fabric. Where the source of heat for heating the air is generated from a residential source of power, such as electricity, the amount of heat available for fabric drying is limited by the capacity of the power supply. In many areas the source of power limits the heat output to unduly lengthen the period of time required to dry the fabric present in the tumbling drum.

An object of the present invention, therefore, is to provide an improved method for drying fabric including the use of a source of vaporized drying fluid as the primary means for drying clothes in a tumbling drum type clothes dryer in order to reduce the time required to dry the fabric therein.

A further object of the present invention is to provide an improved method for drying fabric including conditioning a fluid stream passing therethrough by adding a superheated drying fluid as the primary drying agent and adding heated air from a suitable source as a secondary drying agent.

A further object of the invention is to improve a domestic dryer having a rotatable drum for tumbling clothes by the provision of means for evenly distributing a vaporized drying fluid through the clothes tum-bled by the drum for vaporizing the water contained therein; and to provide such a dryer having means for condensing such vaporized water and removing it from the dryer.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a view in perspective of a clothes dryer including the present invention;

FIGURE 2 is a temperature-entropy chart showing various phases of the operation of the invention;

FIGURE 3 is a sectional View taken substantially along the line 33 of FIGURE 1; and

FIGURE 4 is a schematic wiring diagram for controlling the operation of the invention.

Referring now to the drawings, in FIGURES l and 3 a clothes dryer is shown generally at including a superheated source of drying fluid generally designated at 12. The dryer 10 includes side walls 14, 16, a front wall 18, atop 28 and a rear wall 22. A generally cylindrical tumbling drum 24 is rotatably supported within the chamber formed by the walls 14, 16, 18, 22 and top 20 by means of a shaft 26 having one end thereof secured to a perforated rear wall 28 of the drum 24 and having the opposite end thereof directed through a perforated bulkhead 30 spaced forwardly of the rear wall 22 to form a rear machinery compartment, or space, 32. A universal bearing arrangement 34 supported by the bulkhead 38 rotatably supports the shaft 26 and the drum 24. The machinery compartment 32 separates a pulley Patented Mar. 29, 1966 system 36 from the drying chamber or interior 38 of the tumbling drum 24.

The drum 24 includes inlet ports or apertures 40 in the rear wall thereof and outflow ports or apertures 42 in the inside wall 44 of a door arrangement 45. The inlet ports 40 communicate with an annular plenum or inlet chamber 48 defined by the perforated rear wall 28, the perforated bulkhead 30 and an annular seal 50 of felt or other suitable material carried by the rear wall 28 of the drum in sliding sealing engagement with the interior surface of the bulkhead 30. The outlet ports or apertures 42 communicate with a duct 52 formed in the door 45 adjacent the outlet ports 42 in the inside wall 44 thereof. The drum 24 has an outwardly directed flange portion 54 overlying an inwardly directed flange portion 56 on the front wall 18 for providing an access opening interiorly of the drum 24 through which clothes can be inserted therein to the tumbling drum interior 38. The door 45 is axially aligned with the opening formed by the flange 54 and is supported by a hinge 58 on the front wall 18 to open and close the access opening into the tumbling drum 24. The door 45 has an annular seal 60 thereon for sealing an opening in the front wall 18 when closed and further serves as a support for a filter unit 62 located between outlet ports 42 and duct 52 for collecting lint.

A duct 64 disposed below the door 45 communicates with the door duct 52 through an opening 66 in the bottom of the door and is also located in fluid flow relationship with a passageway or conduit 68 leading to the inlet 70 of a blower 72 having the outlet opening 74 thereof connected to a discharge duct 76 for communicating the blower 72 through an opening 78 in the rear wall 22 of the dryer.

A single motor or prime mover 80 drives the blower 72 through a shaft 82 while simultaneously rotating the tumbling drum 24 through the pulley system 36. By virture of the above-described ducts and passageways, air is drawn from an opening 84 in rear wall 22 across an air heater 86 supported by bulkhead 30 within chamber 48 for warming the air before it enters the drum inten'or 38 through the inlet ports 40 in the rear wall of the drum. Air then is drawn through the drum interior 38, the outlet ports or apertures 42 across filter 62, through the door duct 52 from whence it passes through the front duct 64, conduit 68, inlet 70 of the blower 72 and hence through the blower outlet 74, duct 76 and opening 78 to atmosphere.

Referring now more particularly to the source of drying fluid 12, a flash boiler 90 supported without the machinery compartment 32 has a fluid inlet conduit 92 directed thereto communicating with a suitable source of fluid such as a household water system for directing water into boiler 90 where a heater element 94 electrically connected to a source of power heats the water and converts it to steam which is pressurized by a control valve 95 and discharged through a tube 96 directed through rear wall 22, rear bulkhead 30, and rear wall 28 of the drum 24 through a central opening 98 directed axially through the drive shaft 26. The tube 96 extends into the drying chamber or interior 38 at a point substantially centrally located therein and has a nozzle 100 connected to the outlet thereof for evenly distributing steam through clothes agitated by the drum 24. The provision of a source of drying fluid such as that discussed above provides means for boiling off moisture carried by the clothes and, in accordance with certain principles of the present invention, serves as the primary heat source for drying the clothes in the dryer 10.

In accordance with other features of the present invention the inlet line 92 has a portion 102 thereof coiled in heat transfer relationship with the air discharge duct 76 whereby warm air passing therethrough will preheat the fluid passing into the boiler 90 under the control of a liquid level controlled inlet valve arrangement 104 in line 92. A layer 106 of suitable heat insulation material surrounds the line 92 between portion 102 and the boiler 90 to prevent dissipation of the preheating eifect of duct 76. The coiled portion 102 also serves as a condenser surface for removing moisture from the fluid stream passing through duct 76 with the moisture so removed draining from the duct 76 through a fitting 108.

The operation of the features of this invention will be best understood by referring to the entrophy diagram of FIGURE 2 and the schematic wiring diagram of FIG- URE 4 wherein similar elements carry the same numerals used in conjunction with the dryer structure illustrated in FIGURES 1 and 3. A drying cycle is initiated by placing a load of wet clothes within the tumbling drum 24 through the access opening thereto and a timer dial 110 is then turned to close a switch 112. The motor or prime mover 8% is thus energized by way of L1, a normally closed first timer switch 114 and conductors 116, 118 to- N. Once the motor is energized, it will drive the drum 24 to tumble the clothes therein and concurrently actuate a centrifugal switch 120 in a conductor 122 connected across L1, L2. The conductor 122 serially connects the air heater element 86, a safety switch 124 disposed above heater 86 in the inlet chamber 48 and a cycling thermostat 126 disposed in the front duct 64. The safety switch serves to eliminate dangerous high temperatures within the drying chamber 38 of the drum while the cycling thermostat 126 operates to cycle the heater 86 in maintaining a predetermined desired temperature within the tumbling drum 24. As a further assurance against overheating, the centrifugal switch 120 actuated by energization of the motor 80 is opened whenever the motor is de-energized to prevent the heater 86 from dangerously increasing the temperature in the inlet chamber 48 in cases when air is not being circulated by the blower 72 therethrough. With the above-described components the heater 84 is energized from L1 through conductor 122, a normally open second timer switch 128, cycling thermostat 126, safety switch 124, centrifugal switch 120 to L2.

Concurrently with energization of the motor 80 a timer motor 130 is energized by way of L1, timer switch 114, conductor 116 and a conductor 132 to line N to close the second timer switch 128 and a third timer switch 134 for concurrently energizing the air heater 86 and the boiler heater 94 a predetermined period of time after switch 112 is closed. More particularly, the boiler heater 94 is energized by way of L1, timer switch 114, conductor 116, and a conductor 136 to line N.

Initially, when the boiler 90 is cold the liquid level control inlet valve 104 in the inlet line 92 meters a predetermined charge of water into the boiler 90 to be converted to steam by the heater 94 during the drying cycle. Following energization of the air heater 86 and the boiler heater 94, the operation of the improved drying system. proceeds through an initial phase in which the steam generated by the boiler 90 is pressurized under the control of valve 95 to a predetermined temperature and pressure, for example, approximately 30 p.s.i.a. and 300 F. During this time the blower 72 circulates warm air through the drying chamber 38.

Once the steam reaches the predetermined desired temperature and pressure the control valve 95 will open during a steam phase of operation to direct the steam through tube 96 and nozzle 100 into the drying chamber 38 tobe evenly distributed through the clothes being tumbled therein. Referring now to FIGURE 2, one representative set of operating conditions is illustrated for improving the removal of moisture from such tumbling clothes. The diagram includes a liquid curve 138, a saturation curve 140 and a first pressure curve 142 having a point 144 thereon corresponding to the condition of the steam leaving the nozzle at a superheated state. The steam attains a superheated state since it is at 300 F. in the boiler and as it passes through the nozzle 100 it immediately expands to substantially atmospheric pressure where the 300 F. temperature of the steam constitutes a superheated state. This quickly raises the temperature of the moisture in the clothes tumbling therethrough so that the moisture will boil off and turn to steam. The superheated steam and the moisture driven from the clothes thereby is drawn from the drying chamber 38 by the blower 72 through the outlet ports 42 in the drum at which point the condition of the steam follows a pressure curve 146 having a point 148 thereon in the superheated range at substantially the same entropy as the steam that entered the drum but at a reduced pressure and temperature. The steam is then drawn through the interchanged defined by the coiled portion 102 of the Water inlet line 92 and the discharge duct 76 at which time the steam is condensed to water at point 150 in FIGURE 2 and drained through fitting 108. The superheated steam is continually generated by the boiler 90 for a predetermined period of time under the control of timer motor until a substantial portion of the moisture has been driven from the clothes in the dryer chamber 38 with the time required to remove such moisture being substantially reduced by using superheated steam to vaporize the moisture from the clothes. Following this second, or steam, phase of the dryer operation, the timer motor 130 opens the timer switch 134 to de-energize the boiler heater 94 and thus terminate the passage of steam interiorly of the drum 24. The blower 72 continues to circulate air across the energized heater 86 during a third or secondary phase of the drying operation during which time any remaining moisture is removed from the clothes by warm air passing therethrough. Once the clothes are completely dried by the hot air passing thereover during the third phase, the timer motor 130 will open the timer switch 128 and switch 112 to de-energize the air heater 86 and the motor 80 to thereby complete the drying cycle.

By virtue of the above-described arrangement, it has been found that the use of a drying fluid such as steam to supplement the drying effect of an electric heater or the like substantially reduces the time required to process a load of damp fabric and in accordance with certain of the principles of the present invention uses such a supplemental heat source in an improved method that basically comprises adding superheated drying fiuid such as steam to a circulating air stream and also adding heat thereto; passing the air stream across damp fabric until a substantial portion of the water therein has been converted to steam and removed from the clothes and then terminating the addition of steam and continuing to pass a stream of hot air through the clothes for a predetermined period of time following the steam treatment to assure that the clothes will be essentially completely dry.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a domestic clothes drying device the combination of a rotatable drum for tumbling damp fabric, means for producing superheated steam, means for passing a predetermined amount of said superheated steam interiorly of said drum for vaporizing the liquid contained in the fabric tumbled by said drum, means for circulating air through said drum for extracting steam and vaporized liquid therefrom, and means for heating the air circulating through said drum for providing a final drying cycle supplementing that produced by said superheated steam.

2. In a domestic drying device the combination of a rotatable drum for tumbling damp fabric, a superheated steam generating device including a discharge tube directed interiorly of said rotatable drum. and having the outlet opening thereof located centrally of the interior of said drum for distributing superheated steam evenly through the tumbling fabric, means for maintaining a discharge of superheated steam interiorly of said drum for a predetermined period of time required to raise the temperature of the liquid contained in the fabric sufliciently to substantially convert it to a vaporized state, means for withdrawing the steam and the vaporized liquid from the interior of said drum, and means for passing air at a predetermined temperature through said drum for subjecting the fabric to a final drying cycle until essentially 3. In a domestic clothes drying device the combination of a rotatable drum for tumbling damp fabric, motor means actuatable to drive said rotatable drum, a primary source of heat for drying the liquid containing tumbling fabric including superheated steam generating means having a discharge conduit located interiorly of said drum with the outlet thereof centrally disposed within the drum for evenly distributing superheated steam across the tumbling fabric for converting the liquid contained therein to a vapor state, a secondary source of heat operable concurrently with the first source of heat, means operatively associated with said motor means for circulating air in heat transfer contact with said secondary source of heat and through said tumbling fabric, means for maintaining the discharge of superheated steam from said primary heat source interiorly of said drum for a predetermined period of time required to convert the liquid in the tumbling fabric to a vapor state, said means for circulating air through said drum to continually remove steam and vaporized liquid therefrom for said predetermined period of time, said secondary heat source continuing to operate following termination of steam discharge into said drum until the tumbling fabric is essentially dry.

4. In a domestic clothes drying device the combination of a rotatable drum for tumbling clamp fabric, means for generating superheated steam, means for passing a predetermined amount of said superheated steam interiorly of said drum for vaporizing the liquid contained in the fabric tumbled by said drum, means including a discharge conduit for circulating air through said drum for extracting steam and vaporized liquid therefrom, said superheated steam generating means including a liquid inlet line having a portion thereof located in heat transfer relationship with said discharge conduit for preheating liquid into said generating means and for condensing liquid from the vapor passing through said discharge conduit, and means for draining the liquid condensed in said discharge conduit therefrom.

5. A method for drying damp fabric by conditioning air passing therethrough comprising the steps of adding a predetermined quantity of superheated steam to said air at substantially atmospheric pressure, heating said air independently of said superheated steam, removing said superheated steam from said air, and continuing to heat the air stream passing through the fabric until it is essentially dry.

6. A method for drying liquid containing articles comprising the steps of tumbling liquid containing articles, generating superheated steam, contacting the tumbling articles with the steam at substantially atmospheric pres sure for a predetermined period of time to vaporize the liquid in the tumbling articles, and circulating air through said tumbling articles to remove the steam and vaporized liquid therefrom.

7. A method for drying damp fabric comprising the steps of tumbling the damp fabric, generating a predetermined quantity of superheated steam, heating a stream of air, concurrently passing the steam and heated air through the fabric at substantially atmospheric pressure for vaporizing the liquid therein and removing it therefrom, terminating the generation of steam, and continuing to pass the heated air stream through the fabric until it is essentially dry.

References Cited by the Examiner UNITED STATES PATENTS 2,019,011 10/ 1935 Johnson.

2,189,915 2/1940 Mellor et al. 3427 X 2,198,412 4/ 1940 McDonald.

2,297,314 9/ 1942 Offen 3437 X 2,376,612 5/1945 Muench et al 34-37 X 2,397,091 3/ 1946 Davis.

2,731,732 1/1956 Harris et al 3437 X WILLIAM F. ODEA, Primary Examiner. NORMAN YUDKOFF, Examiner.

J. SOFER, Assistant Examiner. 

6. A METHOD FOR DRYING LIQUID CONTAINING ARTICLES COMPRISING THE STEPS OF TUMBLING LIQUID CONTAINING ARTICLES, GENERATING SUPERHEATED STEAM, CONTACTING THE TUMBLING ARTICLES WITH THE STEAM AT SUBSTANTIALLY ATMOSPHERIC PRESSURE FOR A PREDETERMINED PERIOD OF TIME TO VAPORIZE THE LIQUID IN THE TUMBLING ARTICLES, AND CIRCULATING AIR THROUGH SAID TUMBLING ARTICLES TO REMOVE THE STEAM AND VAPORIZED LIQUID THEREFROM. 